[Raptor]

It really depends on your goals, if you are likely to keep wanting to mod the car, I would start with a good foundation (longblock) and go from there. The points Steve brought up are good for the average DSMer, the factory shortblock is extremely strong as is, and for a car that is in the 400-500 range, should be adequate. Budget and realistic end goals are the main things that should be considered in a decision like this.